The story returns to the Brody family in Amity Island. Martin Brody had died of a heart attack, although his widow, Ellen Brody (Lorraine Gary), claims that "it was the fear of the shark that killed him." Now working as a police deputy, her youngest son Sean (Mitchell Anderson) is dispatched to clear a log from a buoy. As he does so, he is attacked and killed by a shark.

Ellen is convinced that the shark had deliberately targeted Sean, and visits her eldest son, Michael (Lance Guest), in the Bahamas where now works as a marine biologist. Fearing he will be attacked next by the shark, Ellen hopes to convince him to take up a new job on dry land. She meets Hoagie (Michael Caine), and they begin dating. The shark attacks a banana boat, Ellen's granddaughter Thea (Judith Barsi) on it; Thea is unharmed, but her friend's mother is killed (Diane Hetfield). Ellen becomes convinced that the shark has tracked her family to the Bahamas. She takes a boat out to sea on her own, intent on confronting and killing the shark to break the curse, or sacrificing herself hoping the shark will leave her family alone.

Hoagie flies Michael and his friend Jake (Mario Van Peebles) out to sea so that they can find Ellen quickly. Hoagie lands the plane on the sea, but the shark sinks it. Looking out for the shark while using a device that emits electromagnetic impulses to drive the shark mad, Jake moves to the end of the prow. The shark unexpectedly leaps from the surface of the water to grab Jake, biting into him and dragging him beneath the surface. The device causes the shark to repeatedly leap out of the water and Ellen steers the boat directly for the shark, impaling it on the broken bowsprit, which puts pressure on the device and causes it to explode. After killing the shark, they find Jake mauled but alive. The film ends as Hoagie flies Ellen back to Amity Island.